Endocrine Abstracts

JOINT118

Objective: The risk of autoimmune disease could be increased in transgender persons (TG) and susceptibility to autoimmune disease could be affected by transgender care. We assessed the risk of autoimmune diseases in TG compared to controls before and after transgender care.

Methods: A national register-based Danish cohort study was conducted in individuals diagnosed with gender dysphoria between 2000 and 2021. The inclusion date was the date of the first transgender diagnosis. For each case, five age-matched cisgender controls of the same birth sex and five age-matched controls of the opposite birth sex were included. Any autoimmune disease, type 1 diabetes and/or thyroid disease were study outcomes (ICD10 diagnosis of any autoimmune disease and/or medical treatment for type 1 diabetes or thyroid disease).

Results: The cohort included 3, 812 TG and 38, 120 controls. The median age (interquartile range) was 19 (15; 24) years for transmasculine persons (TM), n = 1, 993 and 23 (19; 33) years for transfeminine persons (TF), n = 1, 819. Before the index date, the incidence rate (IR) of type 1 diabetes was significantly higher in TM compared to controls of same birth sex: IRR= 1.98 (1.16; 3.36). In TF vs. controls of same birth sex, the IRR for type 1 diabetes was 1.66 (1.05; 2.61) and for any autoimmune disease was 1.35 (1.04; 1.77). Higher incidence of any autoimmune disease in TG was associated with higher age, medical morbidity, and psychiatric disease. After the index date, the IRR for thyroid disease was 1.98 (1.09; 3.61) in TF vs. controls of same birth sex, whereas the IRR for remaining autoimmune outcomes were comparable between TG and controls of same birth sex. TM using GAHT had higher incidence of autoimmune disease 2.50 (1.10; 5.67) compared to nonusers.

Conclusion: Higher incidence of type 1 diabetes in TG compared to cisgender controls could be attenuated by transgender care.